Seat construction



July 17, 1962 D. E LAWSON 3,044,758

SEAT CONSTRUCTION Filed May 18, 1960 2 Sheets-Sheet 1 INVENTOR. David E.Lawson I BY 2*" 2 Jndrus Star/(e Wife/megs July 17, 1962 D. E. LAWSONSEAT CONSTRUCTION 2 Sheet et 2 Filed May 18, 0

Band E. Lawson BY Vflndms ar/(e United States Patent 3,044,758 SEATCONSTRUCTION David E. Lawson, 2021 Middleton Beach Road, Middleton, Wis.Filed May 18, 1960, Set. 30,031 11 Claims. (Cl. 267-1) layer of foamplastic provides the seat with a degree of softness to the touch, whilethe springs serve to support the load or weight of the person sitting onthe seat. The base support for the springs may either take the form of aseries of support bars, each of which supports a row of springs, or asingle base plate which supports all of the springs. The assembly of theseat of this type and the tying of the springs is time consuming andrequires a substantial amount of hand labor which substantiallyincreases the cost of the seat.

The present invention is directed to a seat foam plastic structure inwhich the foam plastic is reinforced by a metal spiral. Morespecifically, a spiral-shaped, non-resilient reinforcing member formedof fiat strip material is imbedded within and bonded to the foamplastic. The spiral is generally conical in shape and formed with aseries of spaced turns or convolutions of progressively increasingdiameter. The convolution of smallest diam eter is disposed at thebottom of the seat structure and is connected to a support bar, whileeach convolution'or turn vertically overlaps a portion of the next lowerconvolution. A sheet of fabric or wire mesh is disposed over the upperend of the spiral and is similarly imbedded within the foam plastic, andthe layer of the plastic ex tending upwardly beyond the mesh provides acrown or cushion for the seat, providing softness to the touch.

The spiral is not a spring and has no resiliency but merely serves as asupport or skeleton for the foam plastic material. When a load isimparted to the seat structure, the spiral will be compressed and thefoam plastic located between the overlapping portions of the spacedconvolutions is stretched. The resistance of the foam plastic to thisstretching provides a degree of resiliency for the seat which is greaterthan the resilient foam plastic itself.

The seat construction of the invention is soft to the touch, yetprovides firm support for a person sitting thereon. Due to the fact thatno springs are included in the seat cushions, there are no lumps or hardspots in the seat.

The seat structure is economical to fabricate in that low cost materialsare employed and the entire seat can be formed in a single castingoperation which eliminates many of the hand labor operations whichaccompany the normal type of seat fabrication.

As the reinforcement is preferably in the shape of a conical spiral withthe portion of smallest diameter disposed downwardly, the Weight of theperson sitting on the seat will be funneled downwardly to a singlesupport point. This greatly simplifies the supporting structure andagain reduces the overall cost of the seat construction.

Other objects and advantages will appear in the course of the followingdescription.

The drawings illustrate the best mode presently contemplated of carryingout the invention.

In the drawings:

FIGURE 1 is a vertical section of the seat construction of the presentinvention;

FIG. 2 is a top view with parts broken away of the seat shown in FIGURE1;

FIG. 3 is a view similar to FIGURE 1 showing the seat in the compressedposition;

FIG. 4 is a perspective view of the reinforcing spiral employed in theseat construction;

FIG. 5 is a view similar to FIGURE 1 showing a modified form of thereinforcing spiral employed in the seat construction;

FIG. 6 is a view similar to FIG. 5, showing the seat construction in thecompressed position; and

FIG. 7 is a perspective View of the reinforcing spiral employed in theembodiment of FIG. 5.

The drawings illustrate a seat structure which comprises a frame 1 and aseat cushion 2 which is supported by the frame.

The frame 1 includes a pair of side walls 3 and a pair of end walls 4which are connected at their ends to provide a generally rectangularsupport. In addition, a support bar 5, which can either be formed ofwood or metal, is disposed between the end walls 4 and serves as aconnection and support for the seat cushion 2.

The seat cushion 2 includes a body portion 6 formed of a foam plasticmaterial which is reinforced by a spiral 7. In addition, a mesh 8 or webof fabric or metal is disposed over the upper end of the spiral 7 andthe margin of the mesh extends outwardly to adjacent the periphery ofthe cushion 2.

The foam plastic material can be any of the conventional types, such aspolyurethane, polyvinylchloride, polyethylene, polyester blends and thelike.

The reinforcing spiral 7 is generally conical in shape with the end ofsmallest diameter being disposed at the bottom of the seat cushion 2.The spiral is formed from a generally flat strip of metal or reinforcedplastic and each convolution or turn is spaced from the adjacentconvolutions. The spiral is designed so that each convolution overlaps aportion of the adjacent lower convolution.

In addition, each turn or convolution is disposed at an acute angle tothe axis of the spiral with the degree of angularity being generally inthe range of 10 to 60 with respect to the horizontal. turns orconvolutions are disposed at an angle of 30 with respect to thehorizontal.

The uppermost convolution of spiral '7 is provided with an outwardlyextending rim 9 or flange and the mesh 8 rests on the flange. The flangeitself serves to provide agreater area of support for a person sittingon the seat as well as preventing the spiral 7 from cutting through themesh when the seat is compressed. The seat is formed about so that thefoam plastic extends a substantial distance upwardly beyond the mesh 8to provide a cushion or crown 10 for the seat which provides asoftness'to the touch. i r

The lowermost convolution of the spiral terminates in a generally flatbase 11 which rests on the support bar 5. p p

A suitable bolt 12 or the like, serves to connect the spiral '7 to thesupport bar 5 The spiral 7 is not a resilient member and normally, ifexpanded, will fall back to the contracted position under its ownweight. It is not intended that the spiral provide any degree ofresiliency for the seat construction.

The foam plastic is bonded to the surfaces of the spiral I Patented July17, 1962 For most applications, the

for the seat cushion which cannot be achieved by virtue of the foamplastic itself.

More specifically, when a person sits on the seat cushion, the seat iscompressed, as shown in FIG. 3, and the portion of the foam plasticbetween the overlapping portions of adjacent convolutions is deformedand stretched. The resistance to this stretching or tensile stress ofthe plastic provides a degree of resiliency for the seat and provides afirm support which would not be obtainable with the extremely resilientfoam plastic itself.

When subjected to load, the Web 8 serves to distribute the force andserves to unify the compression of the sides of the spiral, or if aseries of spirals are employed in a larger seat construction, it unifiesthe compression of all of the spirals. To provide the required overlapbetween adjacent turns or convolutions and obtain the desired stretchingaction of the plastic foam during compression of the seat, the stripmaterial from-which the spiral is made should generally have a width tothickness ratio in the range of 2:1 to 10:1 and generally in the rangeof about 7:1. If the spiral has a substantially circular cross sectionalconfiguration or if the width and thickness are substantially equal, thestretching action will not be obtained and the turns, duringcompression, will tend to cut through the plastic material and destroythe bond there between and correspondingly destroy the action of thespiral.

The construction shown in FIGS. -7 is a modified form of the inventionin which the spiral 13 used for the reinforcement or skeleton is formedof a generally flat strip of metal or plastic with the convolutionsbeing disposed in planes that are generally perpendicular or normal tothe axis of the spiral. As in the case of the first embodiment, thespiral 13 is not a resilient member and will normally not support itsown weight. Each turn of the spiral vertically overlaps a portion of thenext lower convolution as in the case of the spiral 7. Under loadconditions, as shown in FIG. 6, the spiral is compressed and the foamplastic disposed between the overlapping portions of the convolutions isdistorted and stretched. It is the resistance to this stretching anddistortion which provides the support strength of the seat, with thisresistance being many times greater because of the imbedded flat spiralthan it would be in the case of a foam plastic material alone.

In fabricating the seat construction of the invention, the spiral andthe mesh are located in a suitable mold having the shape of the finishedseat and the foam plastic, then in a liquid condition, is poured orfoamed into the mold. When the foam plastic sets, it adheres tightly tothe convolutions of the spiral as well as to the mesh 8.

It is understood that one or more of the spirals may be imbedded in thefoam plastic seat structure as, for instance, in an automobile cushionwhere two or three such spirals would ordinarily be utilized. Likewise,it will be apparent that the convolutions need not be arcuate orrounded, as shown, but may be of rectangular or oval configurations.Furthermore, while the above description is directed to a spiral havinga series of turns or convolutions, it is contemplated that a series ofseparate rings could be employed in which case each ring would bedisposed with respect to adjacent rings in a manner similar to which theconvolutions of the spiral are located. The stretching and distortion ofthe foam plastic between the overlapping portions of adjacent ringswould provide a function similar to that which results from using thespiral as described above.

This application is a continuation-in-part of application Serial No.714,278, filed February 10, 1958, and entitled Composite Seat Cushion,now abandoned.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim:

1. A seat construction, comprising a frame having a base support member,a seat cushion mounted on the frame and supported by the support member,said seat cushion including a body of substantially resilient foamplastic material and a spiral reinforcement embedded within said bodyand bonded thereto, said spiral reinforcement being formed of a strip ofmaterial having a substantially greater width than thickness and beingsubstantially free of resiliency, said spiral including a series ofconvolutions of progressively increasing diameter with the convolutionof smallest diameter disposed downwardly, each of the convolutions beingspaced from adja' cent convolutions and vertically overlapping a portionof the next lower convolution, the portion of said foam plastic bodydisposed between said overlapping portions being subjected to stretchingand tension stress when a load is applied to said seat cushion and theresistance of said foam plastic providing resiliency for said seatcushion, and means connecting the lowermost of said convolutions to saidsupport member to thereby transfer the load to said support member.

2. A seat structure, comprising a spiral member formed of a strip ofmaterial substantially free of resiliency with said strip havingopposite generally flat surfaces and the width of said strip beingsubstantially greater than the thickness thereof, said spiral memberhaving a series of convolutions of progressively increasing diameterwith the convolution of smallest diameter disposed downwardly, each ofthe convolutions being spaced from adjacent convolutions and verticallyoverlapping a portion of the next lower convolution, and a surroundingbody of substantially resilient foam plastic material bonded to thespiral member and disposed between the overlapping portions of theconvolutions, the portion of said plastic material disposed between saidoverlapping portions being subjected to tension stresses when the loadis imparted to the seat cushion and the resistance of the plasticmaterial to said stresses providing resiliency for the seat cushion.

3. The structure of claim 2 in which each convolution of said strip isdisposed at an angle of 10 to 60 with respect to a horizontal plane.

4. A seat structure, comprising a substantially flat strip of materialdisposed in the form of a helix and defining a series of verticallyspaced turns of progressively increasing diameter with the turn ofsmallest diameter disposed downwardly, each turn of said strip beingdisposed at an acute angle to the vertical axis of the helix andvertically overlapping a portion of the next lower turn, and asurrounding body of foam plastic material surrounding the helix andbonded thereto, the portion of said foam plastic material disposedbetween said overlapping portions being subjected to distortion andstretching when a load is imparted to the seat cushion and theresistance of the plastic material to said distortion and stretchingproviding resiliency for the seat cushion.

5. A seat structure, comprising a substantially flat strip of materialdisposed in the form of a helix and defining a series of verticallyspaced turns of progressively increasing diameter with the turn ofsmallest diameter disposed downwardly, said strip having the Width tothickness ratio in the range of 2: 1 to 10:1 and each turn of said stripbeing disposed to vertically overlap at least a portion of the nextlower turn, and a surrounding body of foam plastic material surroundingthe helix and bonded thereto, the portion of said foam plastic materialdisposed between said overlapping portions being subjected to distortionand stretching when a load is imparted to the seat cushion and theresistance of the plastic material to said distortion and stretchingproviding resiliency for the seat cushion.

6. The structure of claim 5 in which the width to thickness ratio ofsaid strip is approximately 7: 1.

7. A seat structure, comprising a frame having an open top and an openbottom, a support member secured to the frame and extending across theopen bottom thereof, a cushion of foam plastic carried by the frame andsupported on said support member with the upper portion of the cushionextending upwardly beyond the open top of the frame, a spiral memberembedded within and bonded to said foam plastic cushion and formed of astrip of material substantially free of resiliency with said striphaving opposite generally flat surfaces and the width of said stripbeing substantially greater than the thickness thereof, said spiralmember having a series of convolutions of progressively increasingdiameter with the convolution of smallest diameter disposed downwardlyand secured to said support member, each of the convolutions beingspaced from adjacent convolutions and vertically overlapping a portionof the next lower convolution, and a sheet of material of openconstruction disposed across the uppermost of the convolutions andembedded within the foam plastic cushion, the portion of the foamplastic disposed between said overlapping portions being subjected totension stresses when the load is imparted to the seat cushion and theresistance ,of the foam plastic to said stresses providing resiliencyfor the seat cushion and said sheet serving to distribute the load andunify the compression of the spiral.

8. A load supporting structure, comprising a frame, a body of foamplastic supported on the frame, and reinforcing means substantially freeof resiliency imbedded within said body and bonded to the foam plastic,said reinforcing means including a first section and a second section,said first section being spaced above said second section and at leastpartially vertically overlapping said second section, said first andsecond sections having a greater width than thickness and the portion ofthe foam plastic disposed between said overlapping sections beingsubjected to distortion and stretching when a load is'imparted to saidstructure and the resistance of the plastic to said distortion andstretching providing resiliency for the structure.

9. A seat structure, comprisingreinforcing means substantially free ofresiliency and including a series of vertically spaced sections witheach section having a progressively increased diameter with the sectionof smallest diameter disposed downwardly, each of said sections havingopposite generally flat surfaces and the width of said sections beinggreater than the thickness thereofleach of flit; sections being spacedfrom adjacent sections and vertically overlapping a portion of the nextlower section, and a surrounding body of substantially resilient foamplastic material bonded to said reinforcing means and disposed betweenthe overlapping portions of the sections, the portion of said plasticmaterial disposed between said overlapping sections being subjected totension stresses when a load is imparted to the seat cushion, and theresistance of the plastic material to said stresses providing resiliencyfor the seat cushion.

10. A seat structure, comprising a spiral member formed of a strip ofmaterial substantially free of resiliency with said strip havingopposite generally fiat surfaces and the width of said strip beingsubstantially greater than the thickness thereof, said spiral memberhaving a series of convolutions of progressively increasing diameterwith the convolution of smallest diameter disposed downwardly, each ofsaid convolutions being spaced from adjacent convolutions, a cushion ofsubstantially resilient foam plas- 9 tie material bonded to the spiralmember and disposed between the overlapping portions of theconvolutions, and a sheet of reinforcing material disposed above saidspiral and imbedded within said cushion, the portion of said cushionextending above said sheet having a substantial thickness and serving asa crown for the seat structure, the portion of said plastic materialdisposed between the overlapping portions of said convolutions beingsubjected to tension stresses when a load is imparted to the seatstructure and the resistance of the plastic material to said stressesproviding resiliency for the structure.

11. A load supporting structure comprising a frame, a body of foamplastic supported on the frame and having'an upper load-supportingsurface, and reinforcing means substantially free of resiliency imbeddedwithin said body and bonded to the foam plastic, said reinforcing meansincluding a first section and a second section with both said first andsecond sections being disposed at an acute angle to the horizontal, saidfirst section being spaced above said second section and at leastpartially vertically overlapping said second section, said first andsecond sections having a greater width than thickness and a portion ofthe foam plastic disposed between said overlapping sections beingsubjected to distortion and stretching when a load is imparted to saidstructure and the resistance of the plastic to said distortion andstretching providing resiliency for the structure.

References Cited in the file of this patent UNITED STATES PATENTS 16,972Foster et-al Apr. 7, 1857 882,654 Smith Mar. 24, 1908 1,725,479 RissmannAug. 20, 1929 1,963,054 Powers June 12, 1934 2,398,237 Marsack Apr. 9,1946 2,775,287 Mantegna Dec. 25, 1956 2,882,959 Burkart Apr. 21, 1959FOREIGN PATENTS 508,271 France July 20, 1920 559,350 France Apr. 9, 192965,866 Denmark 2 Nov. 10, 1947

